A cheat sheet (also cheatsheet) or crib sheet is a concise set of notes used for quick reference.

Cheat sheets are so named because they may be used by students without the instructor's knowledge to cheat on a test. However, at higher levels of education where rote memorization is not as important as in basic education, students may be permitted to consult their own notes during the exam (which is not considered cheating). The act of preparing a cheat sheet is also an educational exercise, thus students are sometimes only allowed to use cheat sheets they have written themselves. In such usage, a cheat sheet is a physical piece of paper, often filled with equations and/or facts in compressed writing. Modern students often print cheat sheets in extremely small font, fitting an entire page of notes in the palm of their hands during the exam.

The term can also apply to the fully worked solution for exams or work sheets normally handed out to university staff to ease marking.

In more general usage, a "cheat sheet" is any short (one or two page) reference to terms, commands, or symbols where the user is expected to understand the use of such terms but not necessarily to have memorized all of them. Many computer applications, for example, have cheat sheets included in their documentation, which list keystrokes or menu commands needed to achieve specific tasks to save the user the effort of digging through an entire manual to find the keystroke needed to, for example, move between two windows. An example of such a cheat sheet is one for the GIMP photo editing software.[1]

Some academic and technical publishers also publish cheat sheets for software packages and technical topics. In some cases these are also intended as display items in that they are colourful and visually appealing.

Web-based cheat sheets (of the legitimate variety), such as a reference to terms, commands, or symbols, have become extremely common.